Generally, a large-sized transporter vehicle called a dump truck has a liftable vessel (loading platform) on a frame of a vehicle body, and carries and transports objects (for example, crushed stones or earth and sand) to be transported in a state where the objects to be transported are loaded in a large quantity on the vessel (for example, Patent Document 1).
A transporter vehicle of this type according to the conventional art comprises an automotive vehicle body, a loading platform which is tiltably (liftably) provided on the vehicle body and on which the objects to be transported are loaded, a hoist cylinder which is telescopically provided between the loading platform and the vehicle body and expands at the time of dumping the objects from the loading platform to tilt the loading platform diagonally backward of the vehicle body, and a controller for controlling an operation and a stop of the hoist cylinder.
This type of transporter vehicle self-travels to the transportation destination in a state of loading the objects on the loading platform and thereafter, expands the hoist cylinder to diagonally backward raise the loading platform. This raising operation allows the objects to be dumped to a cargo collection site along the tilted loading platform. After such a dumping operation is completed, the hoist cylinder is contracted by a manual operation of an operating lever or the hoist cylinder is contracted by a self-weight in the side of the loading platform. This contraction operation of the hoist cylinder causes the loading platform to be lowered to a position where the loading platform is seated on the vehicle body.